Pelagic trawls include trawls used to catch Alaska Pollock, blue whiting, capelin, herring, mackerel, pearlside, hoki, hake and other fish species. Pelagic trawls have their pelagic mesh formed mainly of ropes. Pelagic mesh in a pelagic trawl is mesh having a mesh size that is four meters (4 m) and greater. A main problem in the pelagic trawl fishing industry and the pelagic trawl net manufacturing industry is high operational costs minimizing profitability. Price competition is severe and thus high cost and high quality ropes such as ropes used in climbing applications, yachting applications and seismic applications, to name a few are not feasible for use in forming the pelagic mesh of pelagic trawls because the pelagic mesh are constantly damaged and replaced, and require replacement even when not damaged as they are made as thin and as light as possible in order to minimize drag and concurrent fuel consumption, and thus are worked at high loads relative to break points and therefore fail rather quickly. For this reason, more costly coverbraided (including “overbraided”) ropes, as opposed to braid jacketed twines used in small mesh netting of say lesser than six hundred millimeters (600 mm), are not favored for forming the pelagic mesh of pelagic trawls. Indeed, considering the world wide pelagic trawl industry as a whole, it is a fact that it is contrary to the state of the art and against the trend in the industry to design and form the pelagic mesh portion of pelagic trawls from coverbraided ropes.
Due to the severe price competition, presently the vast majority of pelagic trawls have their pelagic mesh portion formed of non-jacketed braided or twisted twines. These are low cost to produce, low cost to replace, and easy to splice. It is important that the ropes be easy to splice as splicing has become the dominant form of connecting front part mesh in pelagic trawls as it is much stronger than knotting and also much lower in drug than knotting, allowing much lowered manufacture costs as well as lowered drag and concurrent lowered fuel consumption. The difficulty in splicing coverbraided ropes and especially in splicing tightly coverbraided ropes such as helix ropes is another reason that coverbraided ropes have lost favor among pelagic trawl manufacturers and end users.
One of the main problems caused by the fact that coverbraided ropes are largely out of favor in forming the pelagic mesh portion of pelagic trawls is that the most easily handled and in fact the preferred variant of self spreading meshed trawls employ a coverbraid in the self spreading rope construction and it is self spreading trawls that have the lowest environmental impact of all pelagic trawl constructions. Thus, it is important to increase market demand for self spreading trawls in order to increase the use of low environmental impact pelagic trawls. Ultimately, it is catch per unit effort that is most important to fishing company customers, so newer and better self spreading rope constructions for self spreading trawls must better some factor that the bettering of which improves the catch per unit effort. Likewise, if market demand is to be increased for such self spreading trawls that is pelagic trawls that have the lowest environmental impact of any type of pelagic trawl, such self spreading trawls must increase the catch per unit effort.
The main factor in improving catch per unit effort of pelagic trawls at the rope level is to reduce the drag of a rope at angles of attack found in the pelagic netting portions of pelagic trawls and consequently the drag of a pelagic trawl. The reduced drag concurrently reduces fuel consumption, and also can increase trawl opening. Either or both lead to increased catch per unit effort, and thus lead to increased customer acceptance and demand.
Helix ropes, as defined above and also further defined herein, are used in self spreading pelagic trawls known as “Helix Trawls” manufactured and sold by Hampidjan HF of Iceland. The original teaching of such helix ropes is contained within now Published Patent Cooperation Treaty (PCT) International Publication No. WO/1998/046070. International Application No. PCT/US1998/007848 (see FIG. 29), and a latter teaching of such helix ropes also is contained within now Published Patent Cooperation Treaty (PCT) International Publication No. WO 03/081989 A2, International Application No. PCT/US03/10114 (see FIG. 6). Helix ropes, and the “Helix Trawls” manufactured by Hampidjan HF of Iceland, have acquired a reputation of exhibiting excessively greater drag than modern, state of the art cordage used to form other pelagic trawl nets and especially non-self spreading pelagic trawl nets in the present state of the art. The increased drag concurrently results in smaller trawl openings, reduced towing speed and increase fuel consumption at given tow speeds. For this reason the use of helix ropes to form self spreading trawls such as Helix Trawls has lost favor among fishing entities, despite the fact that they offer other favorable properties, such as eliminating by-catch of marine mammals that would otherwise be caught in non-self spreading trawls when the back end of such non-self spreading trawls collapses around and the marine mammals, enhanced ability to selectively fish as the trawls do not collapse, and other. Problematically, it is the helix ropes that also are the preferred form of a self spreading rope for forming a self spreading pelagic trawl because they are the most reliable embodiment of a self spreading rope useful for forming a self spreading pelagic trawl, other embodiments having lost favor and no longer being in use.
Beyond the highly favorable environmental factors of helix rope formed pelagic trawls, there are other instances when helix rope formed pelagic trawls are highly useful. These include in slow trawl speed applications, and in quick turning applications at deep depths with much warp out, as in these circumstances the self spreading properties of self spreading trawls prevents the trawls from collapsing, thereby not only preventing by-catch of marine mammals and enhancing selective fishing, but also maintaining the trawl fishing the selected species for greater portion of the time. So, where such operational conditions prevail it is favorable to the final catch per unit effort equation to employ even the presently known higher drag and higher cost self spreading trawls formed of the helix rope. However, these circumstances are not the norm, but rather the exception, and in such cases the greater fuel consumption of such trawls is not favored, but rather tolerated and it remains that lowering drag and concurrently lowering fuel consumption is a most important factor in increasing customer demand for such environmentally positive trawls.
Thus, it can readily be appreciated that it is important to reduce the drag of helix ropes so as to reduce the drag of pelagic trawls formed of such helix ropes in order to once again generate favor among fishing entities to use the low environmental impact self spreading trawls that also greatly enhance marine mammal safety and permit more selective fishing, while concurrently reducing fuel consumption per unit of fish caught.
To further describe a helix rope: a helix rope is a type of a “coverbraided” rope, the term “coverbraided” rope also known herein and in the industry as “overbraided” rope. The cover or sheath is formed by a braided sheath that is itself formed of strands. What distinguishes a helix rope from any other type of tightly coverbraided rope useful in forming pelagic mesh in pelagic trawls is that in a helix rope one of the strands forming the braided sheath is substantially larger than the other strands forming the braided sheath. The state and trend of the art in forming any helix rope for the commercial pelagic trawl net industry is to form the braided sheath with the minimum needed count (i.e. quantity) of strands, in order to minimize manufacture costs. That is, the greater the count of strands forming the braided sheath beyond a certain quantity, the greater the manufacture cost. One reason for this is that braiding machinery carrier counts typically are available in eight carriers for more affordable braiding machinery, and sixteen carriers for more expensive braiding machinery. The braiding machinery that forms the braided sheath is progressively more expensive the more carriers that must exist, it being known to those skilled in the art that each carrier provides the material for one of the sheath's strands. As inferred above, due to extreme price competition in the commercial pelagic trawl fish net manufacturing industry, including the manufacturing of components for such commercial pelagic trawl fish nets, helix ropes being one possible such component, pelagic trawl makers as well as manufacturers of components for pelagic trawls acquire and use the least expensive components, methods and machinery for manufacturing such components and pelagic trawls as the customers shall accept, and today most customers are unwilling to pay for a coverbraided rope used to form the front part netting portion of a pelagic trawl.
In fact, as mentioned supra, it is safe to say worldwide that coverbraided ropes are not favored for forming the front part netting portion of pelagic trawls, and that they are constantly loosing favor more and more. Furthermore, due to the fact that as strand count in the braided sheath of any coverbraided rope increases the cost of such rope also progressively increases, it is safe to say that no pelagic trawl manufacturer or even a manufacturer of ropes for sale for use in forming the pelagic mesh portions of pelagic trawls would have any incentive whatsoever to form a braided sheath of any coverbraided rope intended for use in forming pelagic mesh portions of pelagic trawls from any other than a minimum carrier count required for customer acceptance. Thus, with helix ropes having lost favor for use in forming front part netting portions of pelagic trawls due to greater costs, and because the greater the strand count the greater the cost, and as the greatest strand count that ever has been used in any helix rope's braided sheath is sixteen strands, it is safe to say that it is absolutely contrary to the state of the art and against the trend in the industry for any one either to make or believe there is any reason or benefit to be obtained by forming a helix rope with greater than sixteen strands in its coverbraided sheath.
In fact, due to extreme price competition, some rope makers are forming helix ropes with lesser strand counts than are normally deemed by others as adequate for the purpose of rigidity for ease of handling.
It is widely held in the art that very smoothed surface ropes have the greatest drag. In fact, the most popular and widely adopted ropes used for forming the front part portions of pelagic trawls have roughened surfaces, such as conventional twisted and hollow braided non-coverbraided ropes. As taught in the European Patent, it is preferable that the surface of the helix rope's braided sheath be a somewhat roughened surface. Thus, because increasing the strand count progressively decreases surface roughness, and as existing helix ropes' braided sheaths already are considered by those skilled in the art to have a very smooth surface, it can readily be appreciated that there is no hint or suggestion to those skilled in the art to increase the strand count of the helix rope's braided sheath in any attempt to improve drag properties.
Furthermore, known strand counts in braided sheaths in known helix ropes are already considered entirely adequate and even ideal when measured by industry standards and the state of the art and trend in the industry of aesthetic appearance, abrasion resistance, ease of handling and surface smoothness affecting drag. Thus, not only is there great disincentive to those skilled in the art to employ more than minimal known strand counts in forming the coverbraid of any helix rope used in forming any portion of a pelagic trawl net, there also is no positive incentive. In fact there is only the disincentive of extreme price competition that would punish any pelagic trawl component maker or pelagic trawl maker who would make a helix rope or other coverbraided rope for the commercial pelagic trawl fish net industry where such helix rope or other coverbraided rope would have greater than a minimum required count of strands according to industry norms for determining what is suitable for forming the braided sheath of a helix rope, those determinants of industry norms mentioned above and herein.
Because known helix ropes have sheaths that already are considered by industry norms to be suitably abrasion resistant, have ideal aesthetic appearance, optimal rigidity for ease of handling and suitable smoothness, it can readily be appreciated that not only is there great disincentive, no positive incentive, but also there exists no hint or suggestion to those skilled in the art to increase the strand count of the braided sheath of any helix rope beyond known strand counts for forming known helix ropes.
Thus, it can readily again be appreciated that the present state of the art as well as the present trend in the industry teaches one skilled in the art away from using greater than sixteen (16) strands for forming the braided sheath of a helix rope useful for forming the pelagic mesh of a pelagic trawl net.
It is also worthwhile to note that the present state of the art and the current trend in the industry is to form ropes for forming pelagic trawl mesh in such a fashion that all portions of the rope maximally contribute to the overall strength of the rope.